"Genome-wide association studies of adiposity in Samoans" The goal of this new application is to define the genetic variation that underlies obesity and obesity-related phenotypes among adult Samoans. We will use genome-wide association methods to take advantage of newer more powerful techniques to identify single nucleotide polymorphism (SNP) variants that are associated with adiposity phenotypes. We will conduct these studies using a population sample of 2,500 adults from rural areas of Samoa, an independent nation experiencing the nutritional transition. We will replicate the findings from our genome-wide association studies of important SNPs by further analysis in three different study samples: an independent sample of 2,500 Samoans from earlier studies in American Samoa and Samoa, and 1,500 adults from Croatia and 1,000 adults from China. We will then determine the sequences of the important genes and determine the specific genetic variants in the sequenced genes that are associated with obesity in these three samples. Finally, we will explore gene-environment interactions, taking advantage of identified genetic variants in the sequenced regions and the substantial environmental heterogeneity in lifestyle and nutritional behaviors within Samoa. The knowledge gained from this research will aid the development of interventions on obesity amon Samoans including those in the US and may be generalizable to other Pacific Islander groups. PUBLIC HEALTH RELEVANCE: The goal of this application is to define the genetic variation that underlies obesity and obesity-related phenotypes among adult Samoans using genome-wide association methods. Genotyping will be performed using a panel of approximately 900,000 SNPs, and adiposity phenotypes will be collected from 2,500 adult Samoans residing in rural regions of Samoa.